FIELD OF THE INVENTION

This invention relates to an arrestor for a conveyor system and more particularly, but not exclusively, to an arrestor for an inclined chain conveyor system.

BACKGROUND TO THE INVENTION

US patent application number US 2006/0118393 A1 in the name of Hubert Barnard entitled “Conveyor belt arrestor” (“Hubert”) discloses a conveyor belt arrestor, primarily for use with inclined conveyor belts, which operates to arrest the belt in the event that the belt breaks. The arrestor of the invention has a frame which is mounted in use to fixed structure of a conveyor belt installation. The frame includes a reaction member in the form of a beam located above the top run of the belt. A wedging structure is located beneath the top run of the conveyor bell and is mounted for swinging movement in a vertical plane relative to the frame. A torsion spring is tensioned in use to apply a rotational bias to the wedging structure in a direction to swing it upwardly in the event of the belt breaking and belt tension being lost. This lifts the top run of the belt towards the reaction member such that the top run of the belt is trapped between the wedging structure and the reaction member by a wedging action that prevents movement of the top run of the belt in a direction opposite to its normal direction of forward travel.

PCT patent publication number WO2016055882A2 in the name of Pierre Viviers entitled “Conveyor belt arrestor system” (“Viviers”) discloses a conveyor belt arrestor system and more particularly, but not exclusively, a conveyor belt arrestor for use in arresting a conveyor belt used in mining operations in case of failure of the belt. The invention relates to a conveyor belt arrestor system comprising a first arrestor having belt arresting means movable between an open position in which a belt moves freely with respect to the arrestor and a closed position in which a belt is secured by the arresting means and a second arrestor having belt arresting means movable between an open position in which a belt moves freely with respect to the arrestor and a closed position in which a belt is secured by the arresting means, the second arrestor having activating means, when activated allowing the movement of its arresting means from its open to its closed positions and the activating means being activated when the arresting means of the first arrestor moves from its open to its closed position.

In both Hubert and Viviers the documents refer to an arrestor which makes use of a wedging technique to prevent movement of a broken, flexible conveyor belt made of a rubberlike material.

OBJECT OF THE INVENTION

It is an object of this invention to provide an arrestor for an inclined conveyor system which, at least partially, alleviates some of the above-mentioned difficulties.

SUMMARY OF THE INVENTION

In accordance with this invention there is provided an arrestor for an inclined conveyor system comprising a support for supporting a sensor and an arrestor arm, the arrestor arm being movable between a first armed position to a second arresting position when the sensor senses a change of direction of movement of a conveyor belt such as a chain conveyor belt or a pan conveyor so that a catch formation at a free end of the arrestor arm engages a part of the chain of the chain conveyor belt.

The support may be mounted directly above a portion of the chain conveyor belt in order to have the arrestor arm near a link of the chain conveyor belt. This will allow for the catch formation to promptly engage with a link when the arrestor arm moves to the arresting position.

The change of direction of movement of the chain may be caused by a break in the chain or the chain slipping back over a head roller under the force of gravity.

The support may be mounted close to the head roller of a conveyor system as breakages normally, but not in all cases, take place in the vicinity of the head roller.

The sensor may be a mechanical sensor.

The mechanical sensor may be a pawl which engages in between successive links as the chain moves in a first direction. If the chain moves in a second direction the pawl is pushed by the chain links past an activation point to move the arrestor arm to its arresting position.

There is alternatively provided for a sensor to be an electrical or battery powered sensor which makes use of laser or electrical contacts to determine whether there is a change of direction of movement off the chain.

The arrestor arm is in the form of a flat bar being pivotally mounted to the frame at a first end. The catch formation may be a hook formation at the free end of the arm shaped to catch part of a link in the chain.

Alternatively, the catch formation is a protrusion such as a rod from the free end of the arm.

The arrestor arm moves from the armed position to the arresting position under force of gravity, however a biasing means or electric motor or hydraulic means or any other power source may be incorporated to assist in prompt movement as to eliminate any delay in the arresting of the chain.

The arrestor arm is mounted over the top run, or the bottom run of the chain conveyor.

Alternatively, two arrestor arms are mounted over both the top and the bottom run of the chain conveyor. As breakages normally occur in the vicinity of the head roller it is important to arrest both the top and the bottom run in order to minimize downtime for repairs.

The catch formation, when in the arresting position engages with any part of a link in the chain conveyor belt such as a wheel, an axle or any other part of a bogie, hopper or container.

This invention further extends to a method for arresting an inclined conveyor system comprising the steps of: supporting a sensor and an arresting arm to a conveyor system; sensing a change in direction of movement of the conveyor belt; arresting the movement of the conveyor belt by moving an arrestor arm from a first armed position to a second arresting position. The conveyor belt may be a chain conveyor belt or a pan conveyor or any other suitable conveying system, the invention is not limited in this regard.

These and other features of the invention are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention are described below, by way of example only, with reference to the drawings in which:

Figure 1 shows a perspective view from a first angle of an arrestor for an inclined conveyor system in the armed position;

Figure 2 shows the view of Figure 1 of the arrestor in the arresting position;

Figure 3 shows the view of Figure 1 without a conveyor belt;

Figure 4 shows an end view of the arrestor of Figure 1 ;

Figure 5 shows a sectional side view along line V-V in Figure 4 of the arrestor in the armed position;

Figure 6 shows the sectional view of Figure 5 in the arresting position;

Figure 7a shows a second embodiment of an arrestor for an inclined conveyor system in the armed position;

Figure 7b shows the arrestor of Figure 7a with the conveyor moving in an incorrect direction; and

Figure 7c shows the arrestor of Figure 7a in the arresting position. DETAILED DESCRIPTION OF THE DRAWINGS

With reference to the drawings, an arrestor for an inclined conveyor system is generally indicted by reference numeral 1.

The arrestor has a support 2 which is used for supporting a sensor 3 and an arrestor arm 4.

The arrestor arm 4 is movable between a first armed position, as shown in figure 1 and a second arresting position as shown in figure 2.

When the sensor 3 senses movement of a chain conveyor belt 5 opposite to its normal direction of movement, the arrestor arm 4 is released from the armed position so that a catch formation 6 at a free end 7 of the arrestor arm 4 engages a link 8 of the chain 9 of the conveyor belt 5.

The support 2 is mounted directly above a portion of the chain conveyor 5 in order to have the arrestor arm 4 near a link 8 to allow for the catch formation 6 to promptly engage with a link when the arrestor arm 4 is in the arresting position. The embodiment described herein is not limited in this regard and it is possible for the support to be mounted in any position best suited for its application.

The change of direction of movement of the chain 9 may be caused by a break in the chain 9 or the chain slipping back over the head roller under the force of gravity or failure of the drive system of the head roller. The support 4 is usually mounted close to the head roller (not shown) of a conveyor system as breakages normally take place in the vicinity of the head roller.

The sensor 3 is a mechanical system such as a pawl (Figure 7) which allows free movement of the conveyor belt 5 in a first direction, however, should the conveyor belt 5 move in a second direction the pawl catches onto a link 8 which in turn causes the arrestor arm 4 to be released from the armed position to be able to move into the arresting position.

Alternatively, the sensor 3 is an electrical sensor which makes use of laser or electrical contacts to determine whether there is a change of direction of movement off the conveyor belt 5.

The arrestor arm 4 is in the form of a flat bar being pivotally mounted to the frame 2 at a first end.

The catch formation 6 may be a hook formation at the free end of the arm shaped to catch part of a link 8 in the chain 9.

The arrestor arm 4 moves from the armed position to the arresting position under force of gravity, however a biasing means such as a spring or even an explosive charge or an electric motor may be incorporated to assist in prompt movement of the arrestor arm 4 to eliminate any delay in the arresting of the chain 9.

The arrestor arm 4 is mounted over the top run 10 or the bottom run 1 1 of the chain conveyor. Alternatively, two arrestor arms 4 are mounted over both the top 10 and the bottom 1 1 run. As breakages normally occur in the vicinity of the head roller it is important to arrest both the top 10 and the bottom 11 run in order to minimize downtime for repairs. The bottom run 1 1 is arrested to limit damages to other equipment as well as to ensure the safety of personnel working underneath the conveyor system.

If two or more arrestor arms 4 are used, they may be connected to one another so that only one sensor 3 is needed to release any amount of arrestor arms simultaneously.

Figures 5 and 6 show that the catch formation 6, when in the arresting position, engages with any part of a link 8 in the chain such as a wheel 12, an axle 13 or any other part of a bogie, hopper or container.

Figures 7a, 7b and 7c show a second embodiment of the arrestor 1 . Similar reference numerals are used for similar features. The support 2 in the shape of an “A-frame” is mounted directly above a portion of the bottom run 1 1 of the chain conveyor 5. This allows for the arrestor arm 4 to be near a link 8 in the bottom run 11 and close to part of a link 15 in the top run 10.

The sensor 3 is a mechanical system having at a first end a pawl 14. The pawl 14 allows free movement of the top run 10 of the conveyor belt 5 in a first direction, however, should the top run 10 move in a second direction the pawl 14 catches onto part of a link 15. The pawl then causes the arrestor arm 4 to be displaced from the armed position. The catch formation 6 at a second end 7 of the arrestor arm 4 will promptly engage with a link 8 when the arrestor arm 4 is displaced into the arresting position. In use, the arrestor for an inclined conveyor system 1 will act as a safety device. If the direction of movement of the conveyor belt 5 changes, the sensor 3 will sense this and will activate the arrestor arm 4 to move from the armed position to be able to move into the arresting position.

It is envisaged that the arrestor for an inclined conveyor system described herein will ensure not only the safety of humans, but also minimise damage to other equipment, and to reduce downtime for repairs in the event of a chain conveyor belt breaking. Immediately when the belt breaks the belt is arrested to avoid injury, damage or spillage.

It will be appreciated by those skilled in the art that the invention is not limited to the precise details as described herein. The invention may be incorporated with any appropriate conveying system such as a pan conveyor, a bucket conveyor, chain driven conveyor, belt conveyor or the like.